simplify string

alib2data/src/string/StringBase.cpp

@@ -15,10 +15,6 @@
 namespace string {
-StringBase::StringBase() {
-
-}
-
 StringBase::~StringBase() noexcept {
 }

alib2data/src/string/StringBase.h

@@ -16,8 +16,6 @@
 	
 namespace string {
-class String;
-
 class LinearString;
 class CyclicString;
 class Epsilon;
@@ -27,7 +25,6 @@ class Epsilon;
  */
 class StringBase : public std::elementBase<Epsilon, LinearString, CyclicString> {
 public:
-	StringBase();
 	virtual ~StringBase() noexcept;
 	virtual StringBase* clone() const = 0;
@@ -57,12 +54,6 @@ public:
 	virtual void operator>>(std::ostream& out) const = 0;
 	virtual operator std::string () const = 0;
-
-	friend class String;
-
-	friend class Epsilon;
-	friend class LinearString;
-	friend class CyclicString;
 };
 } /* namespace string */